How to interpret and apply the results of indirect calorimetry studies: a case-based tutorial.

Evidence is growing that the individual adjustment of energy targets guided by indirect calorimetry (IC) can improve outcome. With the development of a new generation of devices that are easier to use and rapid, it appears important to share knowledge and expertise that may be used to individualize nutrition care. Despite the focus of this tutorial being on one contemporary device, the principles of IC apply across existing devices and can assist tailoring the nutrition prescription and in assessing response to nutrition therapy. The present tutorial addresses its clinical application in intubated mechanically ventilated and spontaneously breathing adult patients (canopy), i.e. it covers the range from critical illness to outpatients. The cases that are presented show how the measured energy expenditure (mEE), and the respiratory quotient (RQ), i.e. the ratio of expired CO2 to consumed O2, should be applied in different cases, to adapt and individualize nutrition prescription, as it is a good marker of over- or underfeeding at the different stages of disease. The RQ also informs about the patient's body's capacity to use different substrates: the variations of RQ indicating the metabolic changes revealing insufficient or excessive feeding. The different cases reflect the use of a new generation device as a metabolic monitor that should be combined with other clinical observations and laboratory biomarkers. The tutorial also points to some shortcomings of the method, proposing alternatives.

Evaluating predictive equations for energy requirements throughout breast cancer trajectory: A comparative study.

BACKGROUND & AIMS: Accurately estimating resting energy requirements is crucial for optimizing energy intake, particularly in the context of patients with varying energy needs, such as individuals with cancer. We sought to evaluate the agreement between resting energy expenditure (REE) predicted by 40 equations and that measured by reference methods in women undergoing active breast cancer treatment stage (I-IV) and post-completion (i.e., survivors). METHODS: Data from 4 studies were combined. REE values estimated from 40 predictive equations identified by a systematic search were compared with REE assessed by indirect calorimetry (IC) using a metabolic cart (MC-REE N = 46) or a whole-room indirect calorimeter (WRIC-REE N = 44). Agreement between methods was evaluated using Bland-Altman and Lin's concordance coefficient correlation (Lin's CCC). RESULTS: Ninety participants (24 % survivors, 61.1% had early-stage breast cancer I or II, mean age: 56.8 ± 11 years; body mass index: 28.7 ± 6.4 kg/m2) were included in this analysis. Mean MC-REE and WRIC-REE values were 1389 ± 199 kcal/day and 1506 ± 247 kcal/day, respectively. Limits of agreement were wide for all equations compared to both MC and WRIC (∼300 kcal for both methods), including the most commonly used ones, such as Harris-Benedict and Mifflin ST. Jeor equations; none had a bias within ±10% of measured REE, and all had low agreement per Lin's CCC analysis (<0.90). The Korth equation exhibited the best performance against WRIC and the Lvingston-Kohlstadt equation against MC. Similar patterns of bias were observed between survivors and patients and between patients with stages I-III versus IV cancer. CONCLUSION: Most equations failed to accurately predict REE at the group level, and none were effective at the individual level. This inaccuracy has significant implications for women with or surviving breast cancer, who may experience weight gain, maintenance, or loss due to inaccurate energy needs estimations. Therefore, our research underscores the need for further efforts to improve REE estimation.

Nutrition therapy in non-intubated patients with acute respiratory failure: a narrative review.

Objectives: Non-invasive ventilation use is increasing in patients from acute respiratory failure. However, nutritional assessment and medical nutritional therapy are often missed and patients may be frequently underfed. This review evaluates the tools for nutritional screening and assessment, assesses the use of medical nutritional therapy in various techniques of non invasive ventilation and suggested tools to improve this therapy. Methods, results: A review of the literature was performed to evaluate the tools available to define malnutrition and determine the energy needs of patients requiring non invasive ventilation. Energy and protein intake was assessed in 16 recent papers. High Flow Nasal Cannula Oxygen therapy and non invasive ventilation using mask were described and nutritional therapy determined in each condition.The Global Leadership International Malnutrition Assessment seems to be the best assessment to be recommended. Energy expenditure is optimally obtained by indirect calorimetry. Patients with Non invasive ventilation are even more underfed than patients receiving High Flow Nasal Cannula Oxygen therapy. Conclusions: A better determination of malnutrition, a more adequate energy requirement and an improved energy and protein administration are required in patients with acute respiratory failure treated with non invasive ventilation.

Presentation, management, and outcomes of older compared to younger adults with hospital-acquired bloodstream infections in the intensive care unit: a multicenter cohort study.

PURPOSE: Older adults admitted to the intensive care unit (ICU) usually have fair baseline functional capacity, yet their age and frailty may compromise their management. We compared the characteristics and management of older (≥ 75 years) versus younger adults hospitalized in ICU with hospital-acquired bloodstream infection (HA-BSI). METHODS: Nested cohort study within the EUROBACT-2 database, a multinational prospective cohort study including adults (≥ 18 years) hospitalized in the ICU during 2019-2021. We compared older versus younger adults in terms of infection characteristics (clinical signs and symptoms, source, and microbiological data), management (imaging, source control, antimicrobial therapy), and outcomes (28-day mortality and hospital discharge). RESULTS: Among 2111 individuals hospitalized in 219 ICUs with HA-BSI, 563 (27%) were ≥ 75 years old. Compared to younger patients, these individuals had higher comorbidity score and lower functional capacity; presented more often with a pulmonary, urinary, or unknown HA-BSI source; and had lower heart rate, blood pressure and temperature at presentation. Pathogens and resistance rates were similar in both groups. Differences in management included mainly lower rates of effective source control achievement among aged individuals. Older adults also had significantly higher day-28 mortality (50% versus 34%, p < 0.001), and lower rates of discharge from hospital (12% versus 20%, p < 0.001) by this time. CONCLUSIONS: Older adults with HA-BSI hospitalized in ICU have different baseline characteristics and source of infection compared to younger patients. Management of older adults differs mainly by lower probability to achieve source control. This should be targeted to improve outcomes among older ICU patients.

Nutrition during noninvasive respiratory support.

PURPOSE OF REVIEW: The use of noninvasive techniques [noninvasive ventilation (NIV) or high flow nasal cannula (HFNC) oxygen therapy] to support oxygenation and/or ventilation in patients with respiratory failure has become widespread, even more so since the coronavirus disease 2019 pandemic. The use of these modalities may impair the patient's ability to eat. "To breath or to eat" may become a dilemma. In this review, we identify the patients at risk of malnutrition that require medical nutritional therapy and understand the mechanisms of function of the devices to better give adapted nutritional indications for noninvasive ventilation or high flow nasal cannula. RECENT FINDINGS: The Global Leadership Initiative for Malnutrition has been validated in the Intensive Care setting and can be used in patients requiring NIV. Many patients are underfed when receiving noninvasive ventilation therapies. HFNC may impair the swallowing ability and increase dysphagia while NIV may improve the swallowing reflexes. New technology preventing reflux and ensuring enteral feeding efficacy may increase the medical nutrition therapy safety and provide near-target energy and protein provision. SUMMARY: The patient requiring noninvasive ventilation presents one of the most challenging nutritional challenges. The main steps to improve nutrition administration are to assess nutritional status, evaluate the presence of dysphagia, choose the most adequate tool of respiratory support, and adapt nutritional therapy (oral, enteral, or parenteral) accordingly.

The effect of mechanical ventilation compared to high-flow nasal cannula on gastric residual volume and reflux events using novel automated technology.

BACKGROUND & AIM: High flow nasal cannula (HFNC) oxygen therapy is frequently used following extubation. A case report, utilizing an innovative medical technology (The smART + Platform, ART MEDICAL Ltd., Netanya, Israel) that enables the detection of gastric refluxes and gastric residual volumes (GRV), has suggested that HFNC may be associated with increased reflux events and GRV. This study measured reflux events and GRV using smART+ in mechanically ventilated patients before and after extubation while they were receiving HFNC therapy. We aim to show if there is a significant difference in reflux events and GRV between HFNC users and mechanically ventilated patients. METHODS: This is a post hoc analysis examines data of a randomized controlled trial (RCT) involving critically ill adult patients who received enteral nutrition through the smART + Platform. The study was approved by the local ethics committee. We compared the frequency and amplitude of reflux events and GRV in mechanically ventilated patients. These parameters were assessed both 3 h before extubation and subsequently after extubation when the patients were connected to HFNC. Patients served as their own controls. To evaluate the differences between the pre- and post-extubation measurements, we applied a parametric paired t-test. RESULTS: Ten patients (mean age of 58 years; mean APACHE II score 22; mean 3.9 days of mechanical ventilation) were included. Three hours prior extubation the mean GRV was 4.1 ml/h compared to 14.03 ml/h on HFNC (p = 0.004). The mean frequency of major reflux events was 2.33/h in ventilated patients versus 4.4/h in the HFNC patients (p = 0.73). The mean frequency of major reflux events was 9.17/h in ventilated patients versus 9.83/h in HFNC patients (p = 0.14). CONCLUSIONS: Leveraging the smART + Platform, we demonstrated that the use of HFNC significantly increases GRV compared with patients on mechanical ventilation and may increase the frequency of major reflux events, thereby increasing the risk of aspiration. Further studies are required to support our conclusions.

Urea to creatinine ratio as a predictor of persistent critical illness.

INTRODUCTION: Persistent critical illness (PCI) is a syndrome in which the acute presenting problem has been stabilized, but the patient's clinical state does not allow ICU discharge. The burden associated with PCI is substantial. The most obvious marker of PCI is prolonged ICU length of stay (LOS), usually greater than 10 days. Urea to Creatinine ratio (UCr) has been suggested as an early marker of PCI development. METHODS: A single-center retrospective study. Data of patients admitted to a general mixed medical-surgical ICU during Jan 1st 2018 till Dec 31st 2022 was extracted, including demographic data, baseline characteristics, daily urea and creatinine results, renal replacement therapy (RRT) provided, and outcome measures - length of stay, and mortality (ICU, and 90 days). Patients were defined as PCI patients if their LOS was >10 days. We used Fisher exact test or Chi-square to compare PCI and non-PCI patients. The association between UCr with PCI development was assessed by repeated measures linear model. Multivariate Cox regression was used for 1 year mortality assessment. RESULTS: 2098 patients were included in the analysis. Patients who suffered from PCI were older, with higher admission prognostic scores. Their 90-day mortality was significantly higher than non-PCI patients (34.58% vs 12.18%, p < 0.0001). A significant difference in UCr was found only on the first admission day among all patients. This was not found when examining separately surgical, trauma, or transplantation patients. We did not find a difference in UCr in different KDIGO (Kidney Disease Improving Global Outcomes) stages. Elevated UCr and PCI were found to be significantly associated with 1 year mortality. CONCLUSION: In this single center retrospective cohort study, UCr was not found to be associated with PCI development.

A historical cohort study on predictors for successful weaning from prolonged mechanical ventilation and up to 3-year survival follow-up in a rehabilitation center.

BACKGROUND: We followed prolonged mechanically ventilated (PMV) patients for weaning attempts and explored factors associated with successful weaning and long-term survival. METHODS: This historical cohort study included all adult PMV patients admitted to a single rehabilitation hospital during 2015-2018 and followed for survival according to weaning success up to 3 years or the end of 2021. RESULTS: The study included 223 PMV patients. Of them, 124 (55.6 %) underwent weaning attempts, with 69 (55.6 %) successfully weaned, 55 (44.4 %) unsuccessfully weaned, and 99 patients with no weaning attempts. The mean age was 67 ± 20 years, with 39 % female patients. Age, sex distributions and albumin levels at admission were not significantly different among the groups. The successful weaning group had a 6 % higher proportion of conscious patients than the failed weaning group (55 % vs. 49 %, respectively, p = 0.45). Patients successfully weaned were less frequently treated with antibiotics for 5 days or more than those unsuccessfully weaned (74 % vs 80 %, respectively, p = 0.07). They also had a lower proportion of time from intubation to tracheostomy greater than 14 days (45 % vs 66 %, p = 0.02). The age, sex, antibiotic treatment, time to tracheostomy exceeding 14 days and time from admission to first weaning attempt adjusted one-year mortality risk of successful vs. failed weaning was somewhat lower, HR = 0.75, 95%CI: 0.33-1.60, p = 0.45, with the same trend by the end of 3 years, HR = 0.77, 95%CI: 0.42-1.39, p = 0.38. CONCLUSION: Successful weaning from PMV may be associated with better survival and allows chronically ventilated patients to become independent on a ventilator. A larger study is needed to further validate our findings.

Global availability of parenteral nutrition: Pre- and post-COVID-19 pandemic surveys.

OBJECTIVE: Parenteral nutrition represents a therapeutic option for patients with type 3 intestinal failure. If used exclusively, parenteral nutrition has to be complete to provide all essential nutrients. The aim was to assess the availability of parenteral nutrition in all parts of the world, to better comprehend the global situation, and to prepare an action plan to increase access to parenteral nutrition. METHODS: An international survey using an electronic questionnaire was conducted in August 2019 and repeated in May 2022. An electronic questionnaire was sent to 52 members or affiliates of the International Clinical Nutrition Section of the American Society for Parenteral and Enteral Nutrition. Questions addressed the availability of parenteral nutrition admixtures and their components, reimbursement, and prescribing pre- and post-COVID-19 pandemic. All participating countries were categorized by their economic status. RESULTS: Thirty-six country representatives responded, answering all questions. Parenteral nutrition was available in all countries (100%), but in four countries (11.1%) three-chamber bags were the only option, and in six countries a multibottle system was still used. Liver-sparing amino acids were available in 18 (50%), kidney-sparing in eight (22.2%), and electrolyte-free in 11 (30.5%) countries (30.5%). In most countries (n = 28; 79.4%), fat-soluble and water-soluble vitamins were available. Trace elements solutions were unavailable in four (11.1%) countries. Parenteral nutrition was reimbursed in most countries (n = 33; 91.6%). No significant problems due to the coronavirus pandemic were reported. CONCLUSIONS: Despite the apparent high availability of parenteral nutrition worldwide, there are some factors that may have a substantial effect on the quality of parenteral nutrition admixtures. These shortages create an environment of inequality.

Insights from home parenteral nutrition infusion data.

OBJECTIVE: Patients with chronic intestinal failure use home parenteral nutrition infusion support. Non-compliance of home parenteral nutrition treatment is well documented, especially if clinical resources are remote. Objective delivery data from Infusion Pump reports have the potential to support treatment progress and planning. The aim of this study was to report the efficacy and accuracy of the Eitan Insights digital health platform for home parenteral nutrition use (a platform providing data-driven insights from the pump-recorded data). METHODS: A prospective, single-center observational study of 20 patients treated with home parenteral nutrition ≥3 d/wk was conducted over 2022. The patients recorded the pre- and postinfusion home parenteral nutrition bag weight, duration of infusion, and alarms. We compared manual records to the pump data. Repeated measures analysis of variance was used for statistical analysis. RESULTS: A total of 45 data sets were collected, with no adverse events noted. In multiple comparisons between patient factors and descriptive statistics, there was no significant difference between manually recorded and pump-recorded data for volume infused (mean values of manual versus pump were 1707 ± 362 mL and 1708 ± 405 mL; P = 0.939) and infusion duration (mean values of manual versus pump iwere 9h 43 min ± 2.48 SD versus 9h 45 min ± 2.41 SD; P = 0.858). CONCLUSION: The data collected by the digital platform accurately reflect patients' infusion data. This connected device has the potential to allow clinicians to be more informed and assess treatment trends and proactive resource planning through the Infusion Pump data insights.

Predicting invasive mechanical ventilation in COVID 19 patients: A validation study.

INTRODUCTION: The decision to intubate and ventilate a patient is mainly clinical. Both delaying intubation (when needed) and unnecessarily invasively ventilating (when it can be avoided) are harmful. We recently developed an algorithm predicting respiratory failure and invasive mechanical ventilation in COVID-19 patients. This is an internal validation study of this model, which also suggests a categorized "time-weighted" model. METHODS: We used a dataset of COVID-19 patients who were admitted to Rabin Medical Center after the algorithm was developed. We evaluated model performance in predicting ventilation, regarding the actual endpoint of each patient. We further categorized each patient into one of four categories, based on the strength of the prediction of ventilation over time. We evaluated this categorized model performance regarding the actual endpoint of each patient. RESULTS: 881 patients were included in the study; 96 of them were ventilated. AUC of the original algorithm is 0.87-0.94. The AUC of the categorized model is 0.95. CONCLUSIONS: A minor degradation in the algorithm accuracy was noted in the internal validation, however, its accuracy remained high. The categorized model allows accurate prediction over time, with very high negative predictive value.

The future of artificial intelligence in clinical nutrition.

PURPOSE OF REVIEW: Artificial intelligence has reached the clinical nutrition field. To perform personalized medicine, numerous tools can be used. In this review, we describe how the physician can utilize the growing healthcare databases to develop deep learning and machine learning algorithms, thus helping to improve screening, assessment, prediction of clinical events and outcomes related to clinical nutrition. RECENT FINDINGS: Artificial intelligence can be applied to all the fields of clinical nutrition. Improving screening tools, identifying malnourished cancer patients or obesity using large databases has been achieved. In intensive care, machine learning has been able to predict enteral feeding intolerance, diarrhea, or refeeding hypophosphatemia. The outcome of patients with cancer can also be improved. Microbiota and metabolomics profiles are better integrated with the clinical condition using machine learning. However, ethical considerations and limitations of the use of artificial intelligence should be considered. SUMMARY: Artificial intelligence is here to support the decision-making process of health professionals. Knowing not only its limitations but also its power will allow precision medicine in clinical nutrition as well as in the rest of the medical practice.

Implementation of the ESPEN guideline on clinical nutrition in the intensive care unit (ICU): It is time to move forward!: A position paper from the 'nutrition in the ICU' ESPEN special interest group.

Nutritional assessment and provision of nutritional therapy are a core part of intensive care unit (ICU) patient treatment. The ESPEN guideline on clinical nutrition in the ICU was published in 2019. However, uncertainty and difficulties remain regarding its full implementation in daily practice. This position paper is intended to help ICU healthcare professionals facilitate the implementation of ESPEN nutrition guidelines to ensure the best care for their patients. We have aimed to emphasize the guideline recommendations that need to be implemented in the ICU, are advised, or are optional, and to give practical directives to improve the guideline recommendations in daily practice. These statements were written by the members of the ICU nutrition ESPEN special interest group (SIG), based on a survey aimed at identifying current practices relating to key issues in ICU nutrition. The ultimate goal is to improve the ICU patients quality of care.

Metabolic and nutritional aspects in continuous renal replacement therapy.

Nutrition is one of the foundations for supporting and treating critically ill patients. Nutritional support provides calories, protein, electrolytes, vitamins, and trace elements via the enteral or parenteral route. Acute kidney injury (AKI) is a common and devastating problem in critically ill patients and has significant metabolic and nutritional consequences. Moreover, renal replacement therapy (RRT), whatever the modality used, also profoundly impacts metabolism. RRT and of the extracorporeal circuit impede 'effect the evaluation of a patient's energy requirements by clinicians. Substrates added and removed within the extracorporeal treatment are not always taken into consideration, making treatment even more challenging. Furthermore, evidence on nutritional support during continuous renal replacement therapy (CRRT) is scarce, and there are no clinical guidelines for nutrition adaptations during CRRT in critically ill patients. Most recommendations are based on expert opinions. This review discusses the complex interaction between nutritional support and CRRT and presents some milestones for nutritional support in critically ill patients on CRRT.

Two-hour indirect calorimetry measurement as a predictor of 24-hour energy expenditure in critically ill surgical patients: A longitudinal study.

BACKGROUND: Measuring energy expenditure (EE) by indirect calorimetry (IC) has become the gold standard tool for critically ill patients to define energy targets and tailor nutrition. Debate remains as to the optimal duration of measurements or the optimal time of day in which to perform IC. METHODS: In this retrospective longitudinal study, we analyzed results of daily continuous IC in 270 mechanically ventilated, critically ill patients admitted to the surgical intensive care unit in a tertiary medical center and compared measurements performed at different hours of the day. RESULTS: A total of 51,448 IC hours was recorded, with an average 24-h EE of 1523 ± 443 kcal/day. Night shift (00:00-8:00) was found to have significantly lower EE measurements (mean, 1499 ± 439 kcal/day) than afternoon (16:00-00:00; mean, 1526 ± 435 kcal/day) and morning (8:00-16:00; mean, 1539 ± 462 kcal/day) measurements (P < 0.001 for all). The bi-hourly time frame that most closely resembled the daily mean was 18:00-19:59, with a mean of 1521 ± 433 kcal/day. Daily EE measurements of the continuous IC at days 3-7 of admission showed a trend toward a daily increase in 24-h EE, but the difference was not statistically significant (P = 0.081). CONCLUSIONS: Periodic measurements of EE can differ slightly when performed at various hours of the day, but the error range is small and may not necessarily have a clinical impact. When continuous IC is not available, a 2-h EE measurement between 18:00 and 19:59 can serve as a reasonable alternative.

Controlled enteral nutrition in critical care patients - A randomized clinical trial of a novel management system.

PURPOSE: Nutritional therapy is essential to ICU care. Successful early enteral feeding is hindered by lack of protocols, gastrointestinal intolerance and feeding interruptions, leading to impaired nutritional intake. smART+ was developed as a nutrition management feeding platform controlling tube positioning, reflux, gastric pressure, and malnutrition. This study evaluated the potential of this new ICU care platform to deliver targeted nutrition and improve ICU outcomes. METHODS: Critically ill patients ≥18 years-old, mechanically ventilated and enterally fed, were randomized to receive ESPEN-guideline-based nutrition or smART+ -guided nutrition for 2-14 days. Primary endpoint was average deviation from daily targeted nutrition determined via calculation of energy targets per calorimetry. Secondary endpoints included gastric residual volumes, length of stay (LOS) and length of ventilation (LOV). RESULTS: smART+ achieved a mean deviation from daily targeted nutrition of 10.5% (n = 48) versus 34.3% for control (n = 50), p < 0.0001. LOS and LOV were decreased in the smART+ group versus control (mean LOS: 10.4 days versus 13.7; reduction 3.3 days, adjusted HR 1.71, 95% CI:1.13,2.60, p = 0.012; mean LOV: 9.5 days versus 12.8 days reduction of 3.3 days, adjusted HR 1.64, 95% CI:1.08-2.51, p = 0.021). Feeding goals were met (within ±10%) on 75.7% of days for smART+ versus 23.3% for control (p < 0.001). No treatment-related adverse events occurred in either group. The study was stopped due to success in a planned interim analysis of the first 100 patients. CONCLUSION: The smART+ Platform improved adherence to feeding goals and reduced LOS and LOV versus standard of care in critically ill patients. TRIAL REGISTRATION: NCT04098224; registered September 23, 2019.